import calendar
import contextlib
import datetime
import heapq
import itertools
import os  # noqa
import pathlib
import pickle
import re
import time
import warnings
from collections import defaultdict
from collections.abc import Iterable, Iterator, Mapping
from http.cookies import BaseCookie, Morsel, SimpleCookie
from typing import Union

from yarl import URL

from ._cookie_helpers import preserve_morsel_with_coded_value
from .abc import AbstractCookieJar, ClearCookiePredicate
from .helpers import is_ip_address
from .typedefs import LooseCookies, PathLike, StrOrURL

__all__ = ("CookieJar", "DummyCookieJar")


CookieItem = Union[str, "Morsel[str]"]

# We cache these string methods here as their use is in performance critical code.
_FORMAT_PATH = "{}/{}".format
_FORMAT_DOMAIN_REVERSED = "{1}.{0}".format

# The minimum number of scheduled cookie expirations before we start cleaning up
# the expiration heap. This is a performance optimization to avoid cleaning up the
# heap too often when there are only a few scheduled expirations.
_MIN_SCHEDULED_COOKIE_EXPIRATION = 100
_SIMPLE_COOKIE = SimpleCookie()


class CookieJar(AbstractCookieJar):
    """Implements cookie storage adhering to RFC 6265."""

    DATE_TOKENS_RE = re.compile(
        r"[\x09\x20-\x2F\x3B-\x40\x5B-\x60\x7B-\x7E]*"
        r"(?P<token>[\x00-\x08\x0A-\x1F\d:a-zA-Z\x7F-\xFF]+)"
    )

    DATE_HMS_TIME_RE = re.compile(r"(\d{1,2}):(\d{1,2}):(\d{1,2})")

    DATE_DAY_OF_MONTH_RE = re.compile(r"(\d{1,2})")

    DATE_MONTH_RE = re.compile(
        "(jan)|(feb)|(mar)|(apr)|(may)|(jun)|(jul)|(aug)|(sep)|(oct)|(nov)|(dec)",
        re.I,
    )

    DATE_YEAR_RE = re.compile(r"(\d{2,4})")

    # calendar.timegm() fails for timestamps after datetime.datetime.max
    # Minus one as a loss of precision occurs when timestamp() is called.
    MAX_TIME = (
        int(datetime.datetime.max.replace(tzinfo=datetime.timezone.utc).timestamp()) - 1
    )
    try:
        calendar.timegm(time.gmtime(MAX_TIME))
    except OSError:
        # Hit the maximum representable time on Windows
        # https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/localtime-localtime32-localtime64
        MAX_TIME = calendar.timegm((3000, 12, 31, 23, 59, 59, -1, -1, -1))
    except OverflowError:
        # #4515: datetime.max may not be representable on 32-bit platforms
        MAX_TIME = 2**31 - 1
    # Avoid minuses in the future, 3x faster
    SUB_MAX_TIME = MAX_TIME - 1

    def __init__(
        self,
        *,
        unsafe: bool = False,
        quote_cookie: bool = True,
        treat_as_secure_origin: StrOrURL | Iterable[StrOrURL] | None = None,
    ) -> None:
        self._cookies: defaultdict[tuple[str, str], SimpleCookie] = defaultdict(
            SimpleCookie
        )
        self._morsel_cache: defaultdict[tuple[str, str], dict[str, Morsel[str]]] = (
            defaultdict(dict)
        )
        self._host_only_cookies: set[tuple[str, str]] = set()
        self._unsafe = unsafe
        self._quote_cookie = quote_cookie
        if treat_as_secure_origin is None:
            self._treat_as_secure_origin: frozenset[URL] = frozenset()
        elif isinstance(treat_as_secure_origin, URL):
            self._treat_as_secure_origin = frozenset({treat_as_secure_origin.origin()})
        elif isinstance(treat_as_secure_origin, str):
            self._treat_as_secure_origin = frozenset(
                {URL(treat_as_secure_origin).origin()}
            )
        else:
            self._treat_as_secure_origin = frozenset(
                {
                    URL(url).origin() if isinstance(url, str) else url.origin()
                    for url in treat_as_secure_origin
                }
            )
        self._expire_heap: list[tuple[float, tuple[str, str, str]]] = []
        self._expirations: dict[tuple[str, str, str], float] = {}

    @property
    def quote_cookie(self) -> bool:
        return self._quote_cookie

    def save(self, file_path: PathLike) -> None:
        file_path = pathlib.Path(file_path)
        with file_path.open(mode="wb") as f:
            pickle.dump(self._cookies, f, pickle.HIGHEST_PROTOCOL)

    def load(self, file_path: PathLike) -> None:
        file_path = pathlib.Path(file_path)
        with file_path.open(mode="rb") as f:
            self._cookies = pickle.load(f)

    def clear(self, predicate: ClearCookiePredicate | None = None) -> None:
        if predicate is None:
            self._expire_heap.clear()
            self._cookies.clear()
            self._morsel_cache.clear()
            self._host_only_cookies.clear()
            self._expirations.clear()
            return

        now = time.time()
        to_del = [
            key
            for (domain, path), cookie in self._cookies.items()
            for name, morsel in cookie.items()
            if (
                (key := (domain, path, name)) in self._expirations
                and self._expirations[key] <= now
            )
            or predicate(morsel)
        ]
        if to_del:
            self._delete_cookies(to_del)

    def clear_domain(self, domain: str) -> None:
        self.clear(lambda x: self._is_domain_match(domain, x["domain"]))

    def __iter__(self) -> "Iterator[Morsel[str]]":
        self._do_expiration()
        for val in self._cookies.values():
            yield from val.values()

    def __len__(self) -> int:
        """Return number of cookies.

        This function does not iterate self to avoid unnecessary expiration
        checks.
        """
        return sum(len(cookie.values()) for cookie in self._cookies.values())

    def _do_expiration(self) -> None:
        """Remove expired cookies."""
        if not (expire_heap_len := len(self._expire_heap)):
            return

        # If the expiration heap grows larger than the number expirations
        # times two, we clean it up to avoid keeping expired entries in
        # the heap and consuming memory. We guard this with a minimum
        # threshold to avoid cleaning up the heap too often when there are
        # only a few scheduled expirations.
        if (
            expire_heap_len > _MIN_SCHEDULED_COOKIE_EXPIRATION
            and expire_heap_len > len(self._expirations) * 2
        ):
            # Remove any expired entries from the expiration heap
            # that do not match the expiration time in the expirations
            # as it means the cookie has been re-added to the heap
            # with a different expiration time.
            self._expire_heap = [
                entry
                for entry in self._expire_heap
                if self._expirations.get(entry[1]) == entry[0]
            ]
            heapq.heapify(self._expire_heap)

        now = time.time()
        to_del: list[tuple[str, str, str]] = []
        # Find any expired cookies and add them to the to-delete list
        while self._expire_heap:
            when, cookie_key = self._expire_heap[0]
            if when > now:
                break
            heapq.heappop(self._expire_heap)
            # Check if the cookie hasn't been re-added to the heap
            # with a different expiration time as it will be removed
            # later when it reaches the top of the heap and its
            # expiration time is met.
            if self._expirations.get(cookie_key) == when:
                to_del.append(cookie_key)

        if to_del:
            self._delete_cookies(to_del)

    def _delete_cookies(self, to_del: list[tuple[str, str, str]]) -> None:
        for domain, path, name in to_del:
            self._host_only_cookies.discard((domain, name))
            self._cookies[(domain, path)].pop(name, None)
            self._morsel_cache[(domain, path)].pop(name, None)
            self._expirations.pop((domain, path, name), None)

    def _expire_cookie(self, when: float, domain: str, path: str, name: str) -> None:
        cookie_key = (domain, path, name)
        if self._expirations.get(cookie_key) == when:
            # Avoid adding duplicates to the heap
            return
        heapq.heappush(self._expire_heap, (when, cookie_key))
        self._expirations[cookie_key] = when

    def update_cookies(self, cookies: LooseCookies, response_url: URL = URL()) -> None:
        """Update cookies."""
        hostname = response_url.raw_host

        if not self._unsafe and is_ip_address(hostname):
            # Don't accept cookies from IPs
            return

        if isinstance(cookies, Mapping):
            cookies = cookies.items()

        for name, cookie in cookies:
            if not isinstance(cookie, Morsel):
                tmp = SimpleCookie()
                tmp[name] = cookie  # type: ignore[assignment]
                cookie = tmp[name]

            domain = cookie["domain"]

            # ignore domains with trailing dots
            if domain and domain[-1] == ".":
                domain = ""
                del cookie["domain"]

            if not domain and hostname is not None:
                # Set the cookie's domain to the response hostname
                # and set its host-only-flag
                self._host_only_cookies.add((hostname, name))
                domain = cookie["domain"] = hostname

            if domain and domain[0] == ".":
                # Remove leading dot
                domain = domain[1:]
                cookie["domain"] = domain

            if hostname and not self._is_domain_match(domain, hostname):
                # Setting cookies for different domains is not allowed
                continue

            path = cookie["path"]
            if not path or path[0] != "/":
                # Set the cookie's path to the response path
                path = response_url.path
                if not path.startswith("/"):
                    path = "/"
                else:
                    # Cut everything from the last slash to the end
                    path = "/" + path[1 : path.rfind("/")]
                cookie["path"] = path
            path = path.rstrip("/")

            if max_age := cookie["max-age"]:
                try:
                    delta_seconds = int(max_age)
                    max_age_expiration = min(time.time() + delta_seconds, self.MAX_TIME)
                    self._expire_cookie(max_age_expiration, domain, path, name)
                except ValueError:
                    cookie["max-age"] = ""

            elif expires := cookie["expires"]:
                if expire_time := self._parse_date(expires):
                    self._expire_cookie(expire_time, domain, path, name)
                else:
                    cookie["expires"] = ""

            key = (domain, path)
            if self._cookies[key].get(name) != cookie:
                # Don't blow away the cache if the same
                # cookie gets set again
                self._cookies[key][name] = cookie
                self._morsel_cache[key].pop(name, None)

        self._do_expiration()

    def filter_cookies(self, request_url: URL) -> "BaseCookie[str]":
        """Returns this jar's cookies filtered by their attributes."""
        if not isinstance(request_url, URL):
            warnings.warn(  # type: ignore[unreachable]
                f"The method accepts yarl.URL instances only, got {type(request_url)}",
                DeprecationWarning,
            )
            request_url = URL(request_url)
        # We always use BaseCookie now since all
        # cookies set on on filtered are fully constructed
        # Morsels, not just names and values.
        filtered: BaseCookie[str] = BaseCookie()
        if not self._cookies:
            # Skip do_expiration() if there are no cookies.
            return filtered
        self._do_expiration()
        if not self._cookies:
            # Skip rest of function if no non-expired cookies.
            return filtered
        hostname = request_url.raw_host or ""

        is_not_secure = request_url.scheme not in ("https", "wss")
        if is_not_secure and self._treat_as_secure_origin:
            request_origin = URL()
            with contextlib.suppress(ValueError):
                request_origin = request_url.origin()
            is_not_secure = request_origin not in self._treat_as_secure_origin

        # Send shared cookie
        key = ("", "")
        for c in self._cookies[key].values():
            # Check cache first
            if c.key in self._morsel_cache[key]:
                filtered[c.key] = self._morsel_cache[key][c.key]
                continue

            # Build and cache the morsel
            mrsl_val = self._build_morsel(c)
            self._morsel_cache[key][c.key] = mrsl_val
            filtered[c.key] = mrsl_val

        if is_ip_address(hostname):
            if not self._unsafe:
                return filtered
            domains: Iterable[str] = (hostname,)
        else:
            # Get all the subdomains that might match a cookie (e.g. "foo.bar.com", "bar.com", "com")
            domains = itertools.accumulate(
                reversed(hostname.split(".")), _FORMAT_DOMAIN_REVERSED
            )

        # Get all the path prefixes that might match a cookie (e.g. "", "/foo", "/foo/bar")
        paths = itertools.accumulate(request_url.path.split("/"), _FORMAT_PATH)
        # Create every combination of (domain, path) pairs.
        pairs = itertools.product(domains, paths)

        path_len = len(request_url.path)
        # Point 2: https://www.rfc-editor.org/rfc/rfc6265.html#section-5.4
        for p in pairs:
            if p not in self._cookies:
                continue
            for name, cookie in self._cookies[p].items():
                domain = cookie["domain"]

                if (domain, name) in self._host_only_cookies and domain != hostname:
                    continue

                # Skip edge case when the cookie has a trailing slash but request doesn't.
                if len(cookie["path"]) > path_len:
                    continue

                if is_not_secure and cookie["secure"]:
                    continue

                # We already built the Morsel so reuse it here
                if name in self._morsel_cache[p]:
                    filtered[name] = self._morsel_cache[p][name]
                    continue

                # Build and cache the morsel
                mrsl_val = self._build_morsel(cookie)
                self._morsel_cache[p][name] = mrsl_val
                filtered[name] = mrsl_val

        return filtered

    def _build_morsel(self, cookie: Morsel[str]) -> Morsel[str]:
        """Build a morsel for sending, respecting quote_cookie setting."""
        if self._quote_cookie and cookie.coded_value and cookie.coded_value[0] == '"':
            return preserve_morsel_with_coded_value(cookie)
        morsel: Morsel[str] = Morsel()
        if self._quote_cookie:
            value, coded_value = _SIMPLE_COOKIE.value_encode(cookie.value)
        else:
            coded_value = value = cookie.value
        # We use __setstate__ instead of the public set() API because it allows us to
        # bypass validation and set already validated state. This is more stable than
        # setting protected attributes directly and unlikely to change since it would
        # break pickling.
        morsel.__setstate__({"key": cookie.key, "value": value, "coded_value": coded_value})  # type: ignore[attr-defined]
        return morsel

    @staticmethod
    def _is_domain_match(domain: str, hostname: str) -> bool:
        """Implements domain matching adhering to RFC 6265."""
        if hostname == domain:
            return True

        if not hostname.endswith(domain):
            return False

        non_matching = hostname[: -len(domain)]

        if not non_matching.endswith("."):
            return False

        return not is_ip_address(hostname)

    @classmethod
    def _parse_date(cls, date_str: str) -> int | None:
        """Implements date string parsing adhering to RFC 6265."""
        if not date_str:
            return None

        found_time = False
        found_day = False
        found_month = False
        found_year = False

        hour = minute = second = 0
        day = 0
        month = 0
        year = 0

        for token_match in cls.DATE_TOKENS_RE.finditer(date_str):
            token = token_match.group("token")

            if not found_time:
                time_match = cls.DATE_HMS_TIME_RE.match(token)
                if time_match:
                    found_time = True
                    hour, minute, second = (int(s) for s in time_match.groups())
                    continue

            if not found_day:
                day_match = cls.DATE_DAY_OF_MONTH_RE.match(token)
                if day_match:
                    found_day = True
                    day = int(day_match.group())
                    continue

            if not found_month:
                month_match = cls.DATE_MONTH_RE.match(token)
                if month_match:
                    found_month = True
                    assert month_match.lastindex is not None
                    month = month_match.lastindex
                    continue

            if not found_year:
                year_match = cls.DATE_YEAR_RE.match(token)
                if year_match:
                    found_year = True
                    year = int(year_match.group())

        if 70 <= year <= 99:
            year += 1900
        elif 0 <= year <= 69:
            year += 2000

        if False in (found_day, found_month, found_year, found_time):
            return None

        if not 1 <= day <= 31:
            return None

        if year < 1601 or hour > 23 or minute > 59 or second > 59:
            return None

        return calendar.timegm((year, month, day, hour, minute, second, -1, -1, -1))


class DummyCookieJar(AbstractCookieJar):
    """Implements a dummy cookie storage.

    It can be used with the ClientSession when no cookie processing is needed.

    """

    def __iter__(self) -> "Iterator[Morsel[str]]":
        while False:
            yield None  # type: ignore[unreachable]

    def __len__(self) -> int:
        return 0

    @property
    def quote_cookie(self) -> bool:
        return True

    def clear(self, predicate: ClearCookiePredicate | None = None) -> None:
        pass

    def clear_domain(self, domain: str) -> None:
        pass

    def update_cookies(self, cookies: LooseCookies, response_url: URL = URL()) -> None:
        pass

    def filter_cookies(self, request_url: URL) -> "BaseCookie[str]":
        return SimpleCookie()
